(I2) - Tag number the source segment. This tag number along with the
number to be given in (I3), which identifies the position of the segment
in a set of equal tag numbers, uniquely definer the source segment.
Blank or zero in field (I2) implies that the Source segment will be
identified by using the absolute segment number in the next f field.

(I3) - Equal to m, specifies the mth segment of the set of
segments whose tag numbers are equal to the number set by the previous
parameter. If the previous parameter is zero, the number in (I3) must
be the absolute segment number of the source.

l - the input impedance at voltage sources is always printed directly
before the segment currents in the output. By setting this flag, the
impedance of a single source segment in a frequency loop will be
collected ant printer in a table(in a normalized and unnormalized form)
after the information at all frequencies has been printed. Normalization
to the maximum value is a default, but the nonnalization value can be
specified (refer to F3 under voltage source below). When there is more
than one source on the structure, only the impedance of the last Source
specified will be collected .

(I4) - Only column l9 is used and its function is identical
to that listed under b.

Floating Point Options

a. Voltage source ( (Al) " 0 or A)

(Fl) - Real part of the voltage in volts.

(F2) - Imaginary part of the voltage in volts.
(F3) - If a one Is placed in column 20 (see above), this
field can be used to specify a normalization constants
for the impedance printed in the optional impedance
table. Blank in this field produces normalization
to the maximum value.

(F4), (F5), & (F6) - Blank.

b. Incident plane wave ((11) s 1, 2, or 3). The incident wave
is characterized by the direction of incident ^k wave polarization in
the plane normal to ^k.

(F3) - Eta in degrees. Eta is the polarization angle defined
as the angle between the theta unit vector and the direction of the
electric field for linear polarization or the major ellipse axis for
elliptical polarization. Refer to figure 14,

C. Elementary current source ((I1) - 4). The current source is
characterized by its Cartesian coordinate position, orientation, and its
magnitude.

(F1) - X position in meters.

(F2) - Y position in meters.

(F3) - Z position in meters.

(F4) - a in degrees. a is the angle the current source makes with the
XY plane as illustrated on figure 15.

(F5) - beta in degrees. beta is the angle the projection of the current
source on the XY plane makes with the X axis.

(F6) - "Current moment" of the source. This parameter is equal to the
product Il in amp meters.

Notes:

In the case of voltage sources, excitation cards can be grouped
together in order to specify multiple sources. The maximum number of
voltage sources that may be specified is determined by dimension
statements in the program. The dimensions are set for 10 applied-E-
field voltage sources and 10 current-slope-discontinuity voltage
sources.

The applied-E-field voltage source tat located on the segment
specified.

The current-slope-discontinuity source is located at the
first end, relative to the reference direction, of the specified
segment, at the Junction between the specified segment and the
previous segment. This Junction must be a simple two-segment
Junction. and the two Segments must be parallel with equal lengths
ant radii.

A current-slope-discontinuity voltage source may lie in a symmetry
plane. An applied field voltage source may not lie in a symmetry
plane since a segment may not lie in a symmetry plane. An applied
field voltage source may be used on a wire crossing a symmetry
plane by exciting the two segments on opposite sides of the Symmetry
plane each with half the total voltage, taking account of the
reference directions of the two segments.

An applied field voltage source specified on a segment which has
been impedance-loaded, through the use of an LD card, is connected in
series with the loads An applied field voltage source specified on
the same segment as a network is connected in parallel with the nee-
work port. For the specific care of a transmission line, the source
is in parallel with both the line ant the shunt load. Applied field
voltage sources should be used in these cases since loads and network
connections are located on, rather that between, segments.

Only one incident plane wave or one elementary current source is al-
lowed at a time. Also plane-wave or current-source excitation is not
allowed with voltage sources. If the excitation types are mixed, the
program will use the last excitation type encountered.

When a number of theta and phi angles are specified for an incident
plane-wave excitation, the theta angle changes more rapidly than phi.

The current element source illuminates the structure with the field of
an infinitesimal current element at the specified location. The current
element source cannot be used over a ground plane.